Symbol on dashboard with a car and a lock?

I recently came across a symbol in my mustang gt. The symbol is a car with a lock on it. I had turned the key to start my car and turned the key back right away because I forgot to lock the salon (I was doing a haircut, the salon key is with the rest of my keys) When I came back inside my car to turn it on that symbol was on and my car won't start., any ideas on how to fix it ?

Was parked for the winter, had to boost once because of dead battery, went
to move the car today would not start, so tried to boost, push button
start...nothing message come up to check steering loc...